One aspect of the invention relates to a shielding device for shielding from electromagnetic radiation, and in particular to an integrated shielding device for shielding from electromagnetic radiation for circuit parts of an integrated semiconductor circuit which are to be shielded.
In the realization of highly complex circuits, particularly in integrated semiconductor circuits, an increasingly wide variety of circuit parts or circuit blocks have to be realized, which often influence one another in an undesirable manner. Logic circuit parts may be involved in this case, for example, which cause a crosstalk in the form of coupling of electromagnetic fields into analog circuit parts, for example.
Particularly in the case of radiofrequency transformer circuits, such crosstalk often becomes apparent through undesirable emissions in the form of spurii, that is, secondary lines in the spectrum, or undesirable oscillation. Besides the influence of digital circuit parts on analog circuit parts and the mutual decoupling of radiofrequency circuit parts, a better decoupling of power stages with respect to low-power circuit parts is often required as well.
Such decoupling or shielding of critical circuit parts from the rest of an integrated circuit is at odds, however, with the increasing integration density demanded particularly in the case of integrated semiconductor circuits.
In some integrated circuits (such as e.g. semiconductor circuits), therefore, there is the need to reliably shield specific circuit parts in such a way that either no electromagnetic radiation escapes from these circuit parts or these circuit parts, are not influenced by externally arriving electromagnetic radiation.
By using multichip modules (MCM), sensitive circuit parts have hitherto been transferred and protected against the influence of electromagnetic radiation by using corresponding shielding. In this case, multichip modules (MCM) are understood to be electronic assemblies which may contain a multiplicity of integrated circuit devices (IC chips) and/or a multiplicity of discrete components which are coupled to one another by using a connecting substrate. In this case, multichip modules of this type may include a plurality of semiconductor chips and other discrete components, which may in each case have a dedicated shielding device in the form of a Faraday cage.
Although the principles for such a multichip module design and also the associated production technologies are relatively well known, such conventional technologies have been unable hitherto to enable a production method with low costs and a high volume.
Furthermore, there is the possibility of obtaining a further improvement in the crosstalk behavior by using a corresponding “layout” or “floor planning”, that is to say a positioning of the respective circuit parts in the layout of a semiconductor device and a differential circuit design. An increased space requirement, which is an obstacle to the future increased integration density with its accompanying miniaturization, is disadvantageous in this case, however. Since the attenuation of the electromagnetic fields increases with distance, severe limits are imposed on more extensive integration.